Appliances, such as washing machines, audio-video players and set top boxes, include one or more quadrature signal generators on their respective user interfaces. Examples of quadrature signal generators include, but are not limited to, incremental rotary encoders and hall effect sensors.
In general, the quadrature signal generators track motion and determine an angular position and velocity of a shaft by providing two outputs that are 90° out of phase with each other. In other words, the quadrature signal generators provide quadrature signals in response to movement of the shaft. Such quadrature signals can be decoded either by a microcontroller or by an integrated circuit (IC) dedicated for the purpose.
Generally, several bytes of memory are consumed by coding instructions, which are written in the microcontroller, to decode the quadrature signals. In addition, extra lines or cables are required to interface the microcontroller with the incremental rotary encoder. The burden becomes even more pronounced in complex applications where the microcontroller has to attend to critical tasks as well. On the other hand, ICs that are used for the purpose of decoding quadrature signals are not just complex to implement, but are also cost ineffective. In addition, the ICs occupy a substantial fraction of the board real estate.